Know when and where you're going.
Find out who's going to be interviewing you. Make sure you have a job description. Find out the dress code - dress smart to play it safe.
Know Your Target
Learn what you can about the company. Keep an eye on news in leading weeks for stories about them.
Know Yourself
Know yourself versus what they want. Find out what they want and match yourself with that. Quantify and qualify yourself. Finally, re-read your CV.
Prepare for the Obvious Questions
Prepare for standard questions: strengths, weaknesses etc
Prepare Questions to Ask Them
What would you like to know? Their structure, promotion potential etc. But do not ask obvious questions you could have found out beforehand.